Biomedical subjects

Hiroyuki Kawashima

Publications and source records attributed to Hiroyuki Kawashima.

27 records · Page 2Linked to original sources

PubMed2003

Effect of dexamethasone on growth inhibition and chondrogenic maturation of human chondrosarcoma.

The effect of dexamethasone, a synthetic glucocorticoid, on in vitro and in vivo growth and differentiation of the human chondrosarcoma cell line (OUMS-27) was studied. Cells were treated with various doses of dexamethasone, and increasing doses produced an inhibitory effect on OUMS-27 tumor cell proliferation and induced maturation. Cell counts for OUMS-27 on day 9 ranged from 59% of the control at 10(-8) M to 45% of the control at 10(-5) M dexamethasone. Northern blot analysis revealed that the type II collagen mRNA level in cells given dexamethasone was lower than that in the controls, and the type X collagen mRNA level was higher than that in the controls. Phase-contrast microscopy revealed that cells grown in control medium formed monolayers consisting of small, polygonal cells, whereas dexamethasone-treated cells became larger and more irregular in shape. In the in vivo study the growth rate of masses in nude mice induced by inoculating OUMS-27 cells was also reduced in a dose-dependent manner with dexamethasone administration. These results suggest that dexamethasone caused growth inhibition and induced chondrogenic maturation of human chondrosarcoma cells.

Animals↗

PubMed2003

Activating Gs alpha mutation at the Arg201 codon in liposclerosing myxofibrous tumor.

Liposclerosing myxofibrous tumor (LSMFT) is a benign fibro-osseous lesion that is characterized by mixture of histologic elements including lipoma, fibroxanthoma, myxoma, ischemic ossification, and fibrous dysplasia (FD)-like features. These tissue components are seen in the original reports of FD; however, the relationship between LSMFT and FD is not clear. Point mutation of the alpha subunit of G protein (Gs alpha), which increases cyclic adenosine monophosphate formation, has been recognized as the cause of McCune-Albright syndrome as well as polyostotic and monostotic FD of bone. Gs alpha mutation at the Arg201 codon in 2 patients of LSMFT was demonstrated in the present study. Although direct sequencing analysis using the fresh-frozen materials could not detect the mutation, the polymerase chain reaction fragmentation length polymorphism (PCR-RFLP) disclosed the missense point mutation Gs alpha at the Arg201 codon in 2 cases involving LSMFT. This result strongly suggests that a subset of LSMFT is a variant form of FD.

Aged↗

PubMed2003

Expression of the coxsackievirus and adenovirus receptor in musculoskeletal tumors and mesenchymal tissues: efficacy of adenoviral gene therapy for osteosarcoma.

Recombinant adenovirus is used as a competent vector in a wide spectrum of cancer gene therapies. Adenovirus infection depends on coxsackievirus and adenovirus receptor (CAR)-mediated virus attachment to the cell surface. However, the expression levels of CAR and the efficiency of adenoviral gene transduction in musculoskeletal tumors have not been systematically investigated. To study the feasibility of gene therapy in musculoskeletal tumors, the expression levels of CAR and the antiproliferative effect of an adenovirally transduced wild-type p53 tumor suppressor gene were examined in 15 distinct musculoskeletal tumor cell lines, 19 tumor tissue samples, and the corresponding pathologically unremarkable mesenchymal tissues. The expression levels of the CAR gene were significantly higher in six of seven osteosarcoma cell lines and two of five osteosarcoma tissue samples than in the other cell lines, musculoskeletal tumors, and mesenchymal tissues. CAR expression levels were closely correlated with adenoviral gene transduction efficiency and the antiproliferative effect of a transduced adenoviral p53 gene in the tested cell lines. In addition, an immunocytochemical study confirmed that transfected green fluorescent protein (GFP) borne by Ad-CAG-GFP was expressed at the cell surface of CAR-positive cells. These results indicate that CAR expression is a critical determinant of transduction efficiency in adenovirus-based gene therapy. Most osteosarcomas appeared to express high levels of CAR, and thus adenovirus-mediated p53 gene therapy is likely to be suitable for the treatment of such tumors.

Adenoviruses, Human↗

PubMed2003

Alveolar soft part sarcoma in Japan: multi-institutional study of 57 patients from the Japanese Musculoskeletal Oncology Group.

OBJECTIVE: The clinical features and the management of alveolar soft part sarcoma (ASPS) are not well known. The efficacy of chemotherapy for soft tissue sarcoma, including high-dose ifosfamide and cisplatin, has not been established yet. Some reports suggest ASPS may occur primarily in bone. METHODS: We report on a series of 57 patients with ASPS over 20 years. Their ages ranged from 7 to 75 years (mean 25). RESULTS: There were 37 females and 20 males. Thirteen lesions (23%) showed bone involvement at the primary site, and 6 of them were diagnosed as bone tumors at presentation. Thirty-seven patients had distant metastases at presentation. Tumor size, bone involvement at the primary site and the presence of metastases at presentation were prognostic indicators (p < 0.05). Marginal excision with radiotherapy or wide excision without radiotherapy achieved good local control. Chemotherapy was performed in 47 patients with different regimens. Two patients treated with intra-arterial chemotherapy regimens responded partially, but intravenous chemotherapy with high-dose ifosfamide or cisplatin failed. CONCLUSIONS: ASPS can present primarily as a bone tumor. No advantage of chemotherapy with high-dose ifosfamide or cisplatin could be demonstrated.

Adolescent↗

PubMed2002

A cell line with characteristics of the periodontal ligament fibroblasts is negatively regulated for mineralization and Runx2/Cbfa1/Osf2 activity, part of which can be overcome by bone morphogenetic protein-2.

The periodontal ligament (PDL) is a connective tissue located between the cementum of teeth and the alveolar bone of the mandibula. It plays an integral role in the maintenance and regeneration of periodontal tissue. The cells responsible for maintaining this tissue are thought to be fibroblasts, which can be either multipotent or composed of heterogenous cell populations. However, as no established cell lines from the PDL are available, it is difficult to assess what type of cell promotes all of these functions. As a first step to circumvent this problem, we have cloned and characterized cell lines from the PDL from mice harboring a temperature-sensitive SV 40 large T-antigen gene. RT-PCR and in situ hybridization studies demonstrated that a cell line, designated PDL-L2, mimics the gene expression of the PDL in vivo: it expresses genes such as alkaline phosphatase, type I collagen, periostin, runt-related transcription factor-2 (Runx2) and EGF receptor, but does not express genes such as bone sialoprotein and osteocalcin. Unlike osteoblastic cells and a mixed cell population from the PDL, PDL-L2 cells do not produce mineralized nodules in the mineralization medium. When PDL-L2 cells were incubated in the presence of recombinant human bone morphogenetic protein-2 alkaline phosphatase activity increased and mineralized nodules were eventually produced, although the extent of mineralization is much less than that in osteoblastic MC3T3-E1 cells. Furthermore, PDL-L2 cells appeared to have a regulatory mechanism by which the function of Runx2 is normally suppressed.

3T3 Cells↗

PubMed2002

BE-18591 as a new H(+)/Cl(-) symport ionophore that inhibits immunoproliferation and gastritis.

In our previous papers [e.g. Sato et al., J. Biol. Chem. 273 (1998) 21455-21462], we have shown that prodigiosins can uncouple various H(+)-ATPases through their H(+)/Cl(-) symport activity. BE-18591 is an enamine of 4-methoxy-2,2'-bipyrrole-5-carboxyaldehyde (tambjamine group antibiotics) which resembles the prodigiosins. We found that BE-18591 was a new group of antibiotics that uncouples various H(+)-ATPases: it inhibited proton pump activities with IC(50)s of about 1-2 nM (about 20 pmol/mg protein) for submitochondrial particles as well as gastric vesicles and of 230 nM (about 230 pmol/mg protein) for lysosomes, but it had little effect on their ATP hydrolyses (up to 10 microM), a property of H(+)/Cl(-) symport activity. At low concentrations (<1 microM), BE-18591 inhibited immunoproliferation, the IC(50) of lipopolysaccharide-stimulated mouse splenocytes was 38 nM, that of Concanavalin A-stimulated cells was 230 nM. Gastritis of rabbits was also inhibited. At higher concentrations (>1 microM), BE-18591 induced neurite outgrowth (15% induction in 48 h at 4 microM), inhibited bone resorption (approximately 35% in 48 h at 10 microM) and caused cell death (approximately 30% in 48 h at 4 microM) but with little apoptosis.

Adenosine Triphosphatases↗

PubMed2002

Histological examination of beta-tricalcium phosphate graft in human femur.

Prominent osteoconductive activity and the biodegradable nature of beta tricalcium phosphate (beta-TCP) for bone grafts in animal experiments has been reported. A new type of beta-TCP has been manufactured at extraordinarily high purity and has been available as potent bone grafting substitute for clinical use. The histological features of grafted beta-TCP in human bone have been analyzed. A 33-year-old female with a bone tumor of the proximal femur underwent curettage and beta-TCP graft under the diagnosis of probable benign fibrous dysplasia. Four weeks later, the proximal femur, including the grafted beta-TCP was resected because of the final diagnosis of the curettaged materials was osteosarcoma. The resected specimen revealed abundant direct new bone apposition on beta-TCP. There was no cartilaginous tissue or enchondral ossification. Bone formation was more prominent in the periphery of the grafted area than in the center. There was a considerable number of osteoclast-like giant cells surrounding the beta-TCP. This case illustrated that highly purified beta-TCP had prominent osteoconductive activity and biodegradable nature in human bone.

Absorbable Implants↗

PubMed2002

[Mechanical stress and bone metabolism].

Mechanical stress (MS) is one of the most important factor regulating bone metabolism. However, little is known about the mechanism by which MS contribute to this important biological event. In this paper I will present a brief overview of the hypotheses and data so far presented as well as the ongoing researches elsewhere.

English Abstract↗

PubMedDate not supplied

Activating Gs a mutation rarely occurs in musculoskeletal tumors other than fibrous dysplasia.

BACKGROUND: Activating Gs a mutations have been identified in most instances of fibrous dysplasia (FD). This mutation leads to consistently elevated intracellular cyclic adenosine monophosphate (cAMP) levels, with various biological consequences. The development of secondary sarcoma in FD is a rare but well-established phenomenon. This finding raised the possibility that a common gene mutation exists in these tumors. MATERIALS AND METHODS: The expression of the Gs a mutation was examined in 16 cell lines and 173 musculoskeletal tumor tissues, including 13 cases of FD, via RT-PCR and sequence analysis. RESULTS: No expression of a Gs a mutation was detected in any cell line or clinical tissue sample, excluding FD tissues. Direct sequence analysis demonstrated results identical to those of RT-PCR. CONCLUSION: Activating Gs a mutation rarely occurs in musculoskeletal tumors other than FD. The occurrence of most sarcomas displays no correlation with Gs a mutations.

Bone Neoplasms↗